[hugh3]

Pretty much anyone who was alive in 1620 will by now either have no descendants or a ridiculously large number of descendants.

If his descendants continued to breed at the rate of 2.5 children each at the age of 25 then by now he'd have approximately 1.6 million descendants in the latest generation (plus another million or so from their parents and grandparents' generations, still alive). Bump it up to an average of three children and we're looking at 30 million descendants. Bring the breeding age down to 22 and we're talking 287 million descendants, which just happens to be the population of the US. Of course you'd need to adjust that downwards since there'd be plenty of (mostly rather remote) inbreeding along the way.

If you could get a complete list of your (seven hundred thousand or so) ancestors dating back to the 17th century you'd probably be totally thrilled by the number of famous names on it. But of course, everyone else would have a similar number of famous names on their own.